This section is intended to introduce the reader to various aspects of the art that may be related to various aspects of the present invention. The following discussion is intended to provide information to facilitate a better understanding of the present invention. Accordingly, it should be understood that statements in the following discussion are to be read in this light, and not as admissions of prior art.
The parabolic trough design of concentrated thermal solar frames uses parabolic mirrors to focus and concentrate the sun's energy on an insulated tube filled with heat transfer fluid; this fluid is heated to generally well above 700 d.F. and circulated to a steam turbine power generation plant (See FIGS. 1 and 2).
FIG. 1 is a schematic of concentrated solar parabolic trough system. Parabolic mirrors rotate to track the sun as it traverses the sky. FIG. 2 is a schematic that shows the concept of the parabolic mirrors concentrating the sun's rays onto a small diameter collector tube at the parabola's focal point.
The frames supporting these structures are large, stiff truss-like structures designed to support the weight of the mirrors and the wind loads (which can be substantial) in a manner which both keeps the units structurally sound and minimizes deflections to achieve high conversion efficiencies of the sunlight into energy; any deflections reduce this efficiency.
The frames pivot about a line which is generally the center of mass of the mirrors, tubes and frames combined; this pivoting enables the mirrors to “track” the sun as it traverses across the sky. The current designs use elevated pivot points at each end of the frame with bearings, and drive arms which transfer the rotational forces from one frame to another (a single drive unit turns several frames in the row); generally, these end supports require large footings.
A simple, practical design to dramatically reduce the loads on the pivot points 34 and upon the frame members, resulting in less deflection and improved optical alignment has been developed. This is called the “Rolling Rib” design (and derivations of it, including the incorporation of mirror washing and water reclamation integrated into any solar frame design).